Independent counsel Kenneth W. Starr has expanded his investigation of President Clinton to examine whether Clinton and his close friend Vernon Jordan encouraged a 24-year-old former White House intern to lie to lawyers for Paula Jones about whether the intern had an affair with the president, sources close to the investigation said yesterday.

A three-judge appeals court panel on Friday authorized Starr to examine allegations of suborning perjury, false statements and obstruction of justice involving the president, the sources said. A Justice Department official confirmed that Attorney General Janet Reno had forwarded Starr's request to the panel that oversees independent counsels after Starr had asked her for "expeditious" consideration of his request.

The expansion of the investigation was prompted by information brought to Starr within the past few weeks by a former White House aide who surreptitiously made tape recordings of conversations she had with the former White House intern describing a relationship with Clinton.

The former intern, Monica Lewinsky, began work in the White House in 1995 at age 21 and later moved to a political job at the Pentagon, where she worked with Linda R. Tripp, who had moved there from an administrative job at the White House.

Sources said Tripp provided Starr with audiotapes of more than 10 conversations she had with Lewinsky over recent months in which Lewinsky graphically recounted details of a year-and-a-half-long affair she said she had with Clinton. In some of the conversations  including one in recent days  Lewinsky described Clinton and Jordan directing her to testify falsely in the Paula Jones sexual harassment case against the president, according to sources.

Lewinsky gave a sworn affidavit in connection with the Jones case Jan. 7, and sources who have seen her affidavit said she denied having an affair with Clinton. She is scheduled to be deposed by Jones's lawyers Friday.

White House officials said they were unaware of the expansion of Starr's investigation and referred calls to Robert S. Bennett, the president's lawyer in the Jones case.

"The president adamantly denies he ever had a relationship with Ms. Lewinsky, and she has confirmed the truth of that," said Bennett. "This story seems ridiculous, and I frankly smell a rat."

Neither Bennett nor White House officials would comment on whether the president had conversations with Lewinsky about her testimony. Efforts to reach both Lewinsky and Tripp this week were unsuccessful.

William Ginsburg, an attorney for Lewinsky, confirmed that Starr is investigating his client's involvement with Clinton and said he has talked with Starr's staff. He would not discuss the substance of the case but portrayed his client as an innocent young victim of the political system. He would not comment on whether Lewinsky had a sexual relationship with Clinton.

"If the president of the United States did this  and I'm not saying that he did  with this young lady, I think he's a misogynist," he said. "If he didn't, then I think Ken Starr and his crew have ravaged the life of a youngster."

He added that a young person like Lewinsky can be devastated "if you're not terribly sophisticated and you're misled by the people at the center of the political system, and that includes the president and his staff and the special prosecutor."

William Hundley, who represents Jordan, said he was unaware of the Starr investigation and declined to discuss it. "It's all news to me," he said. "I'm not disputing what you're telling me, but at this time I'm certainly not going to comment and I can assure you that Mr. Jordan would not comment. ... You can rest assured that we're going to cooperate with the authorities."

On the tape recordings made by Tripp, sources said, Lewinsky described her sexual relationship with Clinton and said the president advised her not to worry about the Jones case because Jones's lawyers would not find out about the relationship. Lewinsky said that when she was notified by Jones's lawyers in mid-December that they wanted her testimony, she called the president and he advised her to deny the affair, the sources said.

She said that Clinton then told Lewinsky that Jordan would help figure out what to say, the sources said.

Clinton gave a deposition to Jones's lawyers Saturday. A gag order prohibits lawyers from discussing the proceedings, but a source said Jones's lawyers asked the president about a number of women with whom he has been linked.

The affidavit Lewinsky gave in the Jones case is sealed in federal court in Little Rock. In it, she is named only as a "Jane Doe" and says she should not have to testify in the Jones case because she had no relevant information, according to a source familiar with the document. Lewinsky said she never had a sexual relationship with Clinton, that he never asked for one and that she never benefited or suffered on the job as a result of any sexual overtures, the source said.

James Moody, a lawyer for Tripp, said last night that "Linda has been subpoenaed for the Paula Jones case, and beyond that I cannot comment."

Tripp formerly worked in an administrative position in the Bush White House and then in the White House Counsel's office during the first years of the Clinton administration. She joined the Pentagon press office in August 1994.

Last summer, Tripp was quoted in a Newsweek story about seeing a woman emerge from the Oval Office after she allegedly had a romantic encounter with Clinton. Tripp said Kathleen Willey, another White House aide, appeared in the hallway with her makeup smeared and clothing askew, Tripp said, and told Tripp she had just had an encounter with Clinton.

Willey was subpoenaed by Jones's lawyers and tried to resist testifying but ultimately was forced to tell her story under oath earlier this month. According to a source familiar with her account, she said she went to Clinton seeking a better job and he grabbed her, started kissing and groping her and said, "I've always wanted to do that."

Bennett, Clinton's lawyer, has denied that Clinton engaged in any improper behavior. After the Newsweek story ran, Bennett publicly questioned Tripp's credibility. Some time after that, Tripp began recording her conversations with Lewinsky, who coincidentally was working in the same Pentagon press office.

Lewinsky started at the White House as an unpaid intern in the office of then-Chief of Staff Leon E. Panetta in the summer of 1995 and impressed colleagues there with her dedication, according to a source familiar with her job history. During the government shutdowns later that year, she volunteered to come into work and manned telephones that were left unattended, earning gratitude among White House officials, according to the source.

Lewinsky was hired in December 1995 as a staff assistant in the Office of Legislative Affairs, where she worked in the correspondence section opening and handling letters from members of Congress. At times, according to the source, she would be responsible for delivering correspondence to the Oval Office, usually leaving it with the president's confidential assistants, Nancy Hernreich or Betty Curry, and she sometimes ran into Clinton during these duties.

"She's like 10,000 other kids who come to the White House," said a colleague. "They're all star-struck, and they all want to see him. ... Did I notice that? Yeah. But I didn't see anything beyond that." She left the Pentagon several months ago to move to New York, associates said.

A Justice Department official said there was no question about approving Starr's request.

"Starr made it clear that he needed this," the Justice source said. "We did not want to look like we were slowing down the process." As a result, Reno made her decision "right away."

The source said that Justice officials were shocked by the allegations. "It was really a situation where people were floored," the source said.